Many traditional dairy food products such as cheeses, yoghurts and the like use enzymes and/or microorganisms in order to produce appropriately flavoured and textured end products. Generally, cheeses and related products made by traditional processes require a maturation or ripening time in order to allow such enzymes and/or microorganisms to fully develop the required flavour and texture. Due to the variety of different manufacturing processes currently used there is a general inconsistency in the market place regarding the flavour and texture of dairy products, and cheeses in particular, which are being sold under the same product name, for example, cheddar cheese, edam cheese, and the like.
In addition, as these traditionally made dairy products may contain residual enzymes or active microorganisms they have a limited shelf life and can spoil easily especially if stored under conditions such as elevated temperatures.
This problem is overcome in processed cheese manufacture, a process which generally involves grinding and cooking the traditional cheese with an emulsifying salt to form a homogeneous molten mass which congeals on cooling into a finished cheese-like product of low enzyme and microorganism activity and therefore consistent, uniform texture, stable flavour, and improved shelf life over time compared with traditionally made cheeses. As processed cheese involves further processing of traditional cheese, processed cheese is more expensive to produce. Processed cheeses also tend to be produced with a limited range of textures which are not comparable to the type and range of textures available for traditionally made cheeses. In addition, processed cheese products created are bland in flavour, and contain emulsifying salts. As a result of the addition of emulsifying salts these products can no longer be described as “natural” cheeses.
A process is described in U.S. Pat. No. 6,183,805 for preparing a processed cheese product which does not use a traditionally made cheese and aims to produce processed cheese from milk in a short period of time. Such a simplified process involves the direct conversion of milk without fermentation, enzymatic treatment and/or intermediate steps of forming and separating curds and whey. In this process, pasteurised milk is acidified and subjected to UF to form a UF retentate. The UF retentate is evaporated to form a pre-cheese. The pre-cheese is then cooked with emulsifying salts to form a processed cheese product which is ready for immediately packaging and which has similar organoleptic properties to processed cheeses made by cooking traditional cheeses.
A process is described in U.S. Pat. No. 4,497,834 for preparing a processed cheese product by direct conversion of milk as above whereby milk is first condensed to the approximate proportions of total solids and moisture corresponding to that desired in the final product, lactose concentration in the milk is reduced and flavours and other additives incorporated into the condensed milk before the mixture is gelled by heating. The gelled composition may then be packaged and cooled. The use of emulsifying salts is taught for fat containing cheeses to provide uniform distribution of the fat and to ensure against fat separation. However, a product made by the process of this patent, as disclosed in U.S. Pat. No. 6,183,805, resulted in a doughy product with essentially no cheese or cheese-like structure, essentially no cheese flavour and which, upon melting exhibited unstable emulsions with severe oil-off and a mealy grainy texture. Such products were found to be not acceptable by the inventors of U.S. Pat. No. 6,183,805.
U.S. Pat. No. 6,183,804 describes a further method of producing processed cheese by the direct conversion of milk by first providing a powdered milk protein concentrate, reconstituting the powder, subjecting to fat and pH adjustment and cooking with emulsifying salts to produce a processed cheese product. This process is rapid and efficient, less labour intensive and less costly than traditional cheese making methods. However, as discussed above, the use of emulsifying salts limits the type of cheese able to be made by such a process and would preclude such cheeses from generally being considered as “natural” cheeses.
It would be desirable to provide a rapid manufacturing process for making a fat-containing stable dairy based food product, and in particular a “natural” cheese product, which does not include the use of emulsifying salts or non dairy derived emulsifying agents, and which provides a consistent storage stable product for immediate distribution to the market place.
U.S. Pat. No. 6,177,118 describes a rapid process for making both “natural” and processed cheeses by direct conversion of milk without fermentation or coagulation. This process involves a combination of milk retentate with a dry protein concentrate or isolate. This mixture is heated to 80° C. for two minutes to form a homogenous molten plastic mass which may be packaged immediately and cooled to solidify the cheese product. No emulsifying salts are used in this process and fat is held in solution by simple blending shortly before the high heat melt. The production of the high heat melt makes this process similar to a process for making processed cheese so that only “natural” cheese products having a limited range of textures are likely to be produced by such a process. This “natural” cheese can be used as a base to make a processed cheese by melting, combining with emulsifying salts and heating to 80° C. for two minutes to produce a further homogenous plastic mass, which may be packaged directly and cooled to form a solid processed cheese mass. In addition, U.S. Pat. No. 6,177,118 teaches the addition of starter culture in the process of “natural” cheese production, however, under conditions which do not allow fermentation per se to take place. Such a process further necessitates the use of a subsequent heat treatment step to stop microbial growth to achieve a cheese product having an improved stability and longer shelf life than conventionally made cheese products.
U.S. Pat. No. 5,213,827 discloses a process of producing a precheese or a “natural” cheese. This is implemented by first producing a skim milk retentate, fermenting the retentate and centrifuging to produce a concentration to which additives such as fat, salt, protein, etc may be added before re-fermenting to produce a cheese base. The cheese base may be further processed by fermentation to produce a precheese suitable for use in the manufacture of processed cheese. This precheese may be texturised to produce a “natural” cheese. However, such a “natural” cheese may still be unstable in storage due to the presence of fermenting bacteria.
U.S. Pat. No. 4,205,090 discloses a method of making a “natural” cheese again by first producing a skim milk retentate by ultrafiltration to incorporate whey protein into cheese. Such a UF retentate may then be converted immediately to cheese using the traditional method of addition of starter culture and/or rennet to initiate coagulation. The presence of residual microorganisms and/or enzymes makes the resulting “natural” cheese unstable in storage.
Other workers have used direct acidification processes to manufacture cheeses without the need to use microorganisms. For example, GDL may be used in combination with or in the place of starter cultures. GDL addition to milk or UF retentates reduces pH and results in curd formation which may be directly packaged and marketed. However such processes are generally only used in the production of soft cheeses such as cottage cheese and feta. An overview of the use of GDL is given in European Dairy Magazine No 2 (1989), p61-66.
It would be desirable to provide a rapid process of making a broad range fat-containing stable dairy based food products, and particularly a “natural” cheese product, which does not include the addition of starter culture so that endogenous microbial growth in the final product is not a concern, wherein the final product has a consistent flavour and texture from the time of manufacture, an improved stability and longer shelf life than conventionally made dairy products.
It is an object of the present invention to provide such processes and/or at least to provide the public with a useful choice.